He then tells the couple it's time to read their vows, and Izzie jumps in and says they didn't have time to write anything. But Alex actually has something to say. "Today's the day my life begins." Hmm, sound familiar? But rest easy, he doesn't copy it verbatim, he was just inspired. "All my life I've been just me, just a smart-mouth kid. Today I become a man. Today I become a husband. Today I become accountable to someone other than myself." He says he now is accountable to her and their future together, and promises that he's ready for whatever happens. "Today, Izzie Stevens, our life together begins. And I for one can't wait." She sighs that she loves him and leans in for the kiss, but is stopped by the priest clearing his throat, and Alex tells him to hurry up. Even though he's grown up, there's Old Alex still in there, which is cute. By the power vested in him, etc. etc... he declares them husband and wife. As they kiss, Bailey tries not to cry, Mark puts his arm around Lexie, and Callie kisses Arizona on the cheek. Cristina smiles and then looks for Hunt, who is furrowing his brow per usual as he stares right back. Meredith and Derek beam at each other. Yes, yes, I know there's been a lot of "beaming" this hour but it just describes very well how genuinely happy everyone has seemed!
As we see Alex help Izzie back into bed, she picks up where she left off earlier: "You never know the biggest day of your life is the biggest day. Not until it's happening." The wedding clearly took it out of her, and she's weak and shivering. Once in bed, Alex takes the flowers out of her hair and happens to pull out a lock of it at the same time. She starts to pull more out in horror but he assures her that she doesn't need it. She tells him it's just going to keep falling out, but he tells her they can just shave it off, and that he bets she looks good bald anyway. I think she should be happy that she was able to style it for her wedding and have it look amazing when it actually started coming out that morning, actually. He goes to put her oxygen mask back on when she starts to sob, and he tells her she's beautiful and kisses her.
"You don't recognize the biggest day of your life, not until you're right in the middle of it. The day you commit to something or someone. Callie and Arizona are in bed, laughing and eating pizza.